Howard Hinnant  <hhinnant@apple.com>

	PR libstdc++/26250
	* include/bits/sstream.tcc (basic_stringbuf<>::overflow): Tweak
	to leave epgtr() just past the new write position, as per the
	relevant bits of 27.7.1.3/8 (not changed by DR 432).
	* testsuite/27_io/basic_stringbuf/overflow/char/26250.cc: New.
	* testsuite/27_io/basic_stringbuf/overflow/wchar_t/26250.cc: Same.

	* docs/html/ext/howto.html: Add entries for DR 169 and DR 432.

	* include/std/std_sstream.h (basic_stringbuf<>::_M_sync): Move out
	of line...
	* include/bits/sstream.tcc: ... here.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@111177 138bc75d-0d04-0410-961f-82ee72b054a4